chore: bump version to 0.40

[stdrc]

No description provided.

[Copilot]

Pull Request Overview

This PR bumps the project version from 0.39 to 0.40 and updates the changelog to document a bug fix.

Key Changes:

• Version updated in pyproject.toml from "0.39" to "0.40"
• Changelog entry added documenting a fix for a possible decoding error in Bash tool

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
pyproject.toml	Version number incremented to 0.40
CHANGELOG.md	Added changelog entry for Bash tool decoding error fix

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}